On the growth of structure in theories with a dynamical preferred frame

TL;DR

This paper investigates the stability and structure formation in theories with a dynamical preferred frame, identifying conditions for viable cosmological evolution and growth of cosmic structures.

Contribution

It provides a stability analysis and identifies parameter conditions for structure growth in theories with a dynamical preferred frame.

Findings

Cosmological solutions compatible with observations

Conditions for linear perturbation growth

Parameter constraints for structure formation

Abstract

We study the cosmological stability of a class of theories with a dynamical preferred frame. For a range of actions, we find cosmological solutions which are compatible with observations of the recent history of the Universe: a matter dominated era followed by accelerated expansion. We then study the evolution of linear perturbations on these backgrounds and find conditions on the parameters of the theory which allow for the growth of structure sourced by the new degrees of freedom.